Many fluid cleaning appliances, such as the system illustrated herein, are known for cleaning carpeting and other flooring, wall and upholstery surfaces. The cleaning apparatuses and methods most commonly used today apply cleaning fluid as a spray under pressure to the surface whereupon the cleaning fluid dissolves the dirt and stains and the apparatus scrubs the fibers while simultaneously applying a vacuum or negative pressure to extract the cleaning fluid and the dissolved soil. A high pressure blower is used to generate the strong vacuum necessary for extracting the soiled cleaning fluid and rout it to the cleaning unit's waste storage receptacle.
Prior to fluid cleaning the flooring, it is generally advantageous to initially dry vacuum the surface for removing loose dust and debris which can clog the equipment. This initial dry vacuum cleaning is desirable because, once the carpet is wetted, deep seated dust and debris cannot be drawn from the carpet, even under the vacuum pressures generated by professional fluid cleaning appliances. For the purpose of initial dry vacuum cleaning the carpet, operators have heretofore utilized a conventional dry vacuum cleaner that is independent from the fluid cleaning appliance. The independent dry vacuum cleaning appliance is necessary because fluid cleaning systems do not include filters for separating dry dust and debris from an intake airstream. Rather, dust and dirt dissolved in the soiled cleaning fluid is simply routed to the cleaning unit's liquid waste storage receptacle.
Professional fluid cleaning appliances, such as the systems illustrated herein, operate at much higher pressures than residential vacuum cleaning appliances, on the order of 15-20 inches of mercury for professional fluid cleaning appliances versus 5-8 inches of mercury for residential vacuum cleaning appliances, and, and much high air volumes, on the order of 300-400 cubic feet of air per minute for professional fluid cleaning appliances versus 100 cubic feet per minute for residential vacuum cleaning appliances. These much higher operating pressures and volumes would normally make the use of the professional fluid cleaning appliance more effective than a residential vacuum cleaning appliance in initial dry vacuum cleaning the carpet, and would result in a much cleaner carpet.
Unfortunately, because the blowers generating the vacuum in professional fluid cleaning appliances operate at such high pressures and close mechanical tolerances, any loose dry dust and debris can easily clog them, and if clogged, the blower can quickly burn-out and be destroyed, rendering the cleaning system inoperative. Therefore, the vacuum function of professional fluid cleaning appliances is not operated dry for fear of clogging and burning-out the very sensitive high pressure blower.
Some fluid cleaning appliances do include dry vacuum channels independent of the fluid cleaning channels. These dry vacuum channels can be operated by connecting an independent vacuum source to a vacuum supply line above the cleaning head. Again, the fluid cleaning vacuum source is not utilized for dry vacuum cleaning because of the danger to the high pressure blowers if they become clogged by dust and dirt carried in the intake airstream.
Neither of these conventional dry vacuum cleaning options is satisfactory since each requires the operator to at least bring in a separate vacuum source, if not a complete dry vacuum system independently of the fluid cleaning appliance.
FIG. 1 illustrates a typical prior art professional fluid cleaning system as illustrated in U.S. Pat. No. 6,243,914 issued to the inventor of the present invention and incorporated herein by reference. It is to be understood that this cleaning system is typically mounted in a van or truck for mobile servicing of carpets and flooring in homes and businesses.
The typical prior art fluid cleaning system 1 illustrated in FIG. 1 includes a main liquid waste receptacle 3 into which soiled cleaning fluid is routed. A cleaning head or nozzle 5 is mounted on a rigid vacuum wand 7 which includes a handle 8 for controlling cleaning head 5. A supply of pressurized hot liquid solution of cleaning fluid is supplied to cleaning head 5 via a cleaning solution delivery tube 9 arranged in fluid communication with a cleaning solution inlet orifice 11 of cleaning head 5 for delivering there through a flow of pressurized liquid cleaning solution to fluid cleaning solution spray jets 13 of cleaning head 5. Carpet cleaning head 5 typically includes a rectangular, downwardly open truncated pyramidal envelope 15 which contains the cleaning fluid spray that is applied to the carpet or other flooring, as well as forming a vacuum plenum for the vacuum retrieving the soiled liquid for transport to waste receptacle 3. An intake port 16 of the vacuum wand 7 is coupled in fluid communication with the vacuum plenum of cleaning head 5.
Mounted above the main waste receptacle 3 is a cabinet 17 housing a vacuum source and supply of pressurized hot liquid cleaning fluid. Soiled cleaning fluid is routed from cleaning head 5 into waste receptacle 3 via rigid vacuum wand 7 and a flexible vacuum return hose 19 coupled in fluid communication with an exhaust port 20 thereof, whereby spent cleaning solution and dissolved soil are withdrawn under a vacuum force supplied by the fluid cleaning system, as is well known in the art. A vacuum control valve or switch 21 is provided for controlling the vacuum source 8.
FIG. 2 illustrates details of operation of the typical prior art fluid cleaning system 1 illustrated in FIG. 1. Here, the main waste receptacle 3, as well as the vacuum source and cleaning fluid supply cabinet 17, are shown in partial cut-away views for exposing details thereof. The cleaning fluid is drawn through cleaning solution delivery tube 9 from a supply 23 of liquid cleaning solution in the cabinet 17. The vacuum for vacuum return hose 19 is provided by a vacuum source 25, such as a high pressure blower, driven by a power supply 27. The blower vacuum source 25 communicates with the main waste receptacle 3 through an air intake 29 coupled into an upper portion 31 thereof and, when operating, develops a powerful vacuum in an air chamber 33 enclosed in the receptacle 3.
Vacuum return hose 19 is coupled in communication with waste receptacle 3 through a drain 35, for example, at upper portion 31, remote from intake 29. Vacuum return hose 19 feeds soiled cleaning fluid into waste receptacle 3 as a flow 37 of liquid soiled with dissolved dust, dirt and stains, as well as undissolved particulate material picked up by the vacuum return but of a size or nature as to be undissolvable in the liquid cleaning fluid. The flow 37 of soiled cleaning fluid enters into waste receptacle 3 through drain 35 and forms a pool 39 of soiled liquid filled with dissolved and undissolved debris. A float switch 41 or other means avoids overfilling the waste receptacle 3 and inundating the blower 25 through its air intake 29. A screen or simple filter may be applied to remove gross contaminates from the soiled liquid flow 37 before it reaches the pool 39, but this is a matter of operator choice since any impediment to the flow 37 reduces crucial vacuum pressure at the cleaning head 5 for retrieving the soiled liquid from the cleaned carpet or other surface.
Soiled liquid cleaning fluid effectively filters air drawn into the waste receptacle 3 by dissolving the majority of dust, dirt and stains, and drowning and sinking any undissolved debris whereby it is sunk into the pool 39 of soiled liquid and captured therein. Thus, the soiled liquid in the vacuum return hose 19 effectively filters the air before it is discharged into the enclosed air chamber 34, and no airborne particles of dust and dirt are available to escape into the enclosed air chamber 33 floating above the liquid pool 39.
Because the soiled liquid in the flow 37 from the vacuum return hose 19 and the pool 39 of soiled liquid effectively filter the air in the return from the cleaning head 5, it has been unnecessary to filter the air in the air chamber 33 before it is taken into the blower air intake 29 in order to avoid damage to the sensitive blower 25.
Some operators have installed filters at the blower air intake 29. However, this is believed to be ineffective because the blower 25 operates at such high pressures and volumes, on the order of 2-to-4 times higher vacuum pressures and 3-to-4 times high air volumes over residential vacuum cleaning appliances, as disclosed herein, that airborne dust and debris tend to be sucked straight through any ordinary prior art filter. Furthermore, any ordinary prior art filter that would effectively protect the sensitive high pressure blower 25 from airborne dust and debris would severely impact the vacuum generated at the cleaning head 5 and thereby greatly limit the ability to extract and retrieve the soiled cleaning fluid, leaving behind carpet or flooring that is wet with the soiled cleaning fluid. Therefore, the fluid cleaning appliance does not support an air filter for removing airborne dry dust and debris from the intake airstream, and filters to protect the high pressure blower 25 from airborne dust and debris are not used. Instead, operators simply avoid the danger inherent in exposing the sensitive high pressure blower 25 to airborne dust and debris particles by limiting its use to extracting and retrieving the soiled cleaning fluid, and utilizing a conventional stand-alone dry vacuum cleaning appliance for initial pre-vacuum cleaning the surface before applying the fluid cleaning appliance.
FIG. 3 illustrates another fluid cleaning appliance as illustrated in U.S. patent application Ser. No. 12/378,663 filed Feb. 17, 2009, in the name of the inventor of the present invention and incorporated herein by reference. Here, rigid vacuum wand 7 includes an auxiliary dry vacuum connection 43 for connecting cleaning head 5 to an independent vacuum source 45 via an independent vacuum supply line 47. Dry vacuum connection 43 communicates with dry vacuum cleaning slots 49 adjacent to cleaning solution spray jets 13 in the cleaning head 5. Dry vacuum cleaning slots 49 are sized large enough to receive hair, dirt, gravel and other extraneous large debris. A cleaning solution flow control switch or valve 51 permits switching between the fluid cleaner and dry vacuum processes of the cleaning head 5.
When not in use, auxiliary dry vacuum connection 43 can be sealed by a self-sealing cap or stopper 53.
Thus, in the prior art it was necessary either to dry vacuum the surface using a completely independent dry vacuum cleaner appliance (not shown) for removing loose dust and debris before fluid cleaning using the fluid cleaning system 1, or to dry vacuum using an independent vacuum source 45 connected to the cleaning head 5 via vacuum supply line 47 coupled into the auxiliary dry vacuum connection 43.